Combination watches, wherein an analog watch and digital watch have been integrally combined into one single unit, have come into wide use recently. Such combination watches that are equipped with solar power generation function have also been commercialized as well as ones having various functions added onto.
By referring to FIG. 5 and FIG. 6, an example of the prior art combination watches equipped with a solar power generation unit will be described.
FIG. 5 shows a cross sectional construction (along line 5--5 in FIG. 6) of a prior art combination watch equipped with a solar power generation unit, whereas FIG. 6 shows a plan view of the same watch with the dial removed.
The watch module of this combination electronic watch comprises analog block 1 which constitutes an analog watch as shown in FIG. 5, digital block 2 which is equipped with a liquid crystal member for opto-electronically display time and other information, support 3 for containing and holding said analog block 1 and digital block 2, solar member 4 for generating power, and solar member supporting frame 5 for containing and holding this solar member 4. Dial 6 is positioned on the display side of solar member. Analog block 1 is constituted on main plate 7 as a supporting base.
The combination electronic watch is, as shown in FIG. 6, constructed in such a manner that rotating axes 8 of hour hand 9a, minute hand 9b, and second hand 9c are located slightly toward the side of twelve o'clock from the center, and power generating surface 4a of solar member 4 occupies almost all the display surface of the watch except the digital display unit. Solar member 4 also has an opening 4b which rotating axis 8 of hands 9 passes through. Further, digital block 2, which is positioned approximately in the direction of six o'clock as horizontally seen, is positioned so as not to overlap said solar member 4 as shown in FIG. 5 and FIG. 6.
In addition, when the charge stored in a storage battery decreases to below a predetermined level due to the lack of light, such a combination electronic watch functions to display a warning for charging before it ceases to work as a watch. An analog warning for charging is, as shown in FIG. 6, provided by two second movement, which means that second hand 9c is moved once every two seconds. Whereas, a digital warning for charging is, as shown in FIG. 7, provided by blinking warning mark for charging 10 deposited on a part of digital block 2 for digitally displaying time.
However, the above mentioned combination watch may be improved in the following points.
First, since solar member 4 and digital block 2 are not deposited as being overlapped in the vertical direction toward the dial of the watch, it is impossible for digital block 2 which digitally displays time to be located within the region of power generating surface 4a of solar member 4. Accordingly, the design of the watch is significantly restricted. Although free and various designs are desired in combination watches, it is difficult to design new watches without altering its shape. Thus, in order to design a new watch, the shapes and locations of constituting components such as solar member 4 and digital block 2 must be changed, which causes a significant increase in manufacturing cost. This is why it is difficult to serialize attractive watches while employing the components constituting the above combination watch.
Secondly, since solar member 4 and digital block 2 are not deposited as being overlapped in the above construction, dead space "D", which is not used as a watch display from the design standpoint, necessarily comes to appear as shown in FIG. 6, thereby worsen the space efficiency. It would be preferable if this dead space "D" could be used as power generating surface 4a of solar member 4 so as to improve the capacity of solar power generation.
Thirdly, even though a user recognizes that second hand 9c moves once every two seconds, the user who does not know what is meant by this two second movement may not notice the currently existing charge shortage and possibly misunderstand that the watch has been broken if only the warning display for charging by hands 9 is provided. Further, if only the warning display by a digital display is provided and the displayed warning mark for charging 10 is too small, the user may fail to visually notice the warning mark 10 though a warning display is provided.
Therefore, a purpose of the present invention is to provide a combination electronic watch constructed by depositing a solar cell and a digital block one onto the other in the vertical direction toward the display surface of the watch, forming a window in a part of the solar member, and allowing the digital display of the liquid crystal unit to be transparently displayed through the window, so that the location of the digital block can be freely designed and the space efficiency of power generating surface 12a is improved over conventional watches.
Another purpose of the invention is to provide a combination electronic watch which makes it possible for the user to readily recognize a currently occurring charge shortage by simultaneously providing warning displays for charging both by hands and by a digital display so as to emphasize such a charge shortage status.